Graham, I've trained for decades in aikido and never had a significant hit to my hands training without tsuba. I've also trained with others in other styles as well as people in traditional sword arts. Some of them train with tsuba. In some of those styles I would have received serious injuries to my hands had I *not* had the tsuba in place. Because they do things differently. Not just techniques, but how they train.

The bottom line is that is just depends. It has nothing to do with laziness. Maybe in your astral plane it does, but in my experience nothing could be further from the truth.